/*
 * TLSv1 common routines
 * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "x509v3.h"
#include "tlsv1_common.h"


/*
 * TODO:
 * RFC 2246 Section 9: Mandatory to implement TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
 * Add support for commonly used cipher suites; don't bother with exportable
 * suites.
 */ 

static const struct tls_cipher_suite tls_cipher_suites[] = {
        { TLS_NULL_WITH_NULL_NULL, TLS_KEY_X_NULL, TLS_CIPHER_NULL,
          TLS_HASH_NULL },
        { TLS_RSA_WITH_RC4_128_MD5, TLS_KEY_X_RSA, TLS_CIPHER_RC4_128,
          TLS_HASH_MD5 },
        { TLS_RSA_WITH_RC4_128_SHA, TLS_KEY_X_RSA, TLS_CIPHER_RC4_128,
          TLS_HASH_SHA },
        { TLS_RSA_WITH_DES_CBC_SHA, TLS_KEY_X_RSA, TLS_CIPHER_DES_CBC,
          TLS_HASH_SHA },
        { TLS_RSA_WITH_3DES_EDE_CBC_SHA, TLS_KEY_X_RSA,
          TLS_CIPHER_3DES_EDE_CBC, TLS_HASH_SHA },
         { TLS_DH_anon_WITH_RC4_128_MD5, TLS_KEY_X_DH_anon,
          TLS_CIPHER_RC4_128, TLS_HASH_MD5 },
         { TLS_DH_anon_WITH_DES_CBC_SHA, TLS_KEY_X_DH_anon,
          TLS_CIPHER_DES_CBC, TLS_HASH_SHA },
         { TLS_DH_anon_WITH_3DES_EDE_CBC_SHA, TLS_KEY_X_DH_anon,
          TLS_CIPHER_3DES_EDE_CBC, TLS_HASH_SHA },
        { TLS_RSA_WITH_AES_128_CBC_SHA, TLS_KEY_X_RSA, TLS_CIPHER_AES_128_CBC,
          TLS_HASH_SHA },
        { TLS_DH_anon_WITH_AES_128_CBC_SHA, TLS_KEY_X_DH_anon,
          TLS_CIPHER_AES_128_CBC, TLS_HASH_SHA },
        { TLS_RSA_WITH_AES_256_CBC_SHA, TLS_KEY_X_RSA, TLS_CIPHER_AES_256_CBC,
          TLS_HASH_SHA },
        { TLS_DH_anon_WITH_AES_256_CBC_SHA, TLS_KEY_X_DH_anon,
          TLS_CIPHER_AES_256_CBC, TLS_HASH_SHA }
};

#define NUM_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
#define NUM_TLS_CIPHER_SUITES NUM_ELEMS(tls_cipher_suites)


static const struct tls_cipher_data tls_ciphers[] = {
        { TLS_CIPHER_NULL,         TLS_CIPHER_STREAM,  0,  0,  0,
          CRYPTO_CIPHER_NULL },
        { TLS_CIPHER_IDEA_CBC,     TLS_CIPHER_BLOCK,  16, 16,  8,
          CRYPTO_CIPHER_NULL },
        { TLS_CIPHER_RC2_CBC_40,   TLS_CIPHER_BLOCK,   5, 16,  0,
          CRYPTO_CIPHER_ALG_RC2 },
        { TLS_CIPHER_RC4_40,       TLS_CIPHER_STREAM,  5, 16,  0,
          CRYPTO_CIPHER_ALG_RC4 },
        { TLS_CIPHER_RC4_128,      TLS_CIPHER_STREAM, 16, 16,  0,
          CRYPTO_CIPHER_ALG_RC4 },
        { TLS_CIPHER_DES40_CBC,    TLS_CIPHER_BLOCK,   5,  8,  8,
          CRYPTO_CIPHER_ALG_DES },
        { TLS_CIPHER_DES_CBC,      TLS_CIPHER_BLOCK,   8,  8,  8,
          CRYPTO_CIPHER_ALG_DES },
        { TLS_CIPHER_3DES_EDE_CBC, TLS_CIPHER_BLOCK,  24, 24,  8,
          CRYPTO_CIPHER_ALG_3DES },
        { TLS_CIPHER_AES_128_CBC,  TLS_CIPHER_BLOCK,  16, 16, 16,
          CRYPTO_CIPHER_ALG_AES },
        { TLS_CIPHER_AES_256_CBC,  TLS_CIPHER_BLOCK,  32, 32, 16,
          CRYPTO_CIPHER_ALG_AES }
};

#define NUM_TLS_CIPHER_DATA NUM_ELEMS(tls_ciphers)


/**
 * tls_get_cipher_suite - Get TLS cipher suite
 * @suite: Cipher suite identifier
 * Returns: Pointer to the cipher data or %NULL if not found
 */
const struct tls_cipher_suite * tls_get_cipher_suite(u16 suite)
{
        size_t i;
        for (i = 0; i < NUM_TLS_CIPHER_SUITES; i++)
                if (tls_cipher_suites[i].suite == suite)
                        return &tls_cipher_suites[i];
        return NULL;
}


const struct tls_cipher_data * tls_get_cipher_data(tls_cipher cipher)
{
        size_t i;
        for (i = 0; i < NUM_TLS_CIPHER_DATA; i++)
                if (tls_ciphers[i].cipher == cipher)
                        return &tls_ciphers[i];
        return NULL;
}


int tls_server_key_exchange_allowed(tls_cipher cipher)
{
        const struct tls_cipher_suite *suite;

        /* RFC 2246, Section 7.4.3 */
        suite = tls_get_cipher_suite(cipher);
        if (suite == NULL)
                return 0;

        switch (suite->key_exchange) {
        case TLS_KEY_X_DHE_DSS:
        case TLS_KEY_X_DHE_DSS_EXPORT:
        case TLS_KEY_X_DHE_RSA:
        case TLS_KEY_X_DHE_RSA_EXPORT:
        case TLS_KEY_X_DH_anon_EXPORT:
        case TLS_KEY_X_DH_anon:
                return 1;
        case TLS_KEY_X_RSA_EXPORT:
                return 1 /* FIX: public key len > 512 bits */;
        default:
                return 0;
        }
}


/**
 * tls_parse_cert - Parse DER encoded X.509 certificate and get public key
 * @buf: ASN.1 DER encoded certificate
 * @len: Length of the buffer
 * @pk: Buffer for returning the allocated public key
 * Returns: 0 on success, -1 on failure
 *
 * This functions parses an ASN.1 DER encoded X.509 certificate and retrieves
 * the public key from it. The caller is responsible for freeing the public key
 * by calling crypto_public_key_free().
 */
int tls_parse_cert(const u8 *buf, size_t len, struct crypto_public_key **pk)
{
        struct x509_certificate *cert;

        wpa_hexdump(MSG_MSGDUMP, "TLSv1: Parse ASN.1 DER certificate",
                    buf, len);

        *pk = crypto_public_key_from_cert(buf, len);
        if (*pk)
                return 0;

        cert = x509_certificate_parse(buf, len);
        if (cert == NULL) {
                wpa_printf(MSG_DEBUG, "TLSv1: Failed to parse X.509 "
                           "certificate");
                return -1;
        }

        /* TODO
         * verify key usage (must allow encryption)
         *
         * All certificate profiles, key and cryptographic formats are
         * defined by the IETF PKIX working group [PKIX]. When a key
         * usage extension is present, the digitalSignature bit must be
         * set for the key to be eligible for signing, as described
         * above, and the keyEncipherment bit must be present to allow
         * encryption, as described above. The keyAgreement bit must be
         * set on Diffie-Hellman certificates. (PKIX: RFC 3280)
         */

        *pk = crypto_public_key_import(cert->public_key, cert->public_key_len);
        x509_certificate_free(cert);

        if (*pk == NULL) {
                wpa_printf(MSG_ERROR, "TLSv1: Failed to import "
                           "server public key");
                return -1;
        }

        return 0;
}


int tls_verify_hash_init(struct tls_verify_hash *verify)
{
        tls_verify_hash_free(verify);
        verify->md5_client = crypto_hash_init(CRYPTO_HASH_ALG_MD5, NULL, 0);
        verify->md5_server = crypto_hash_init(CRYPTO_HASH_ALG_MD5, NULL, 0);
        verify->md5_cert = crypto_hash_init(CRYPTO_HASH_ALG_MD5, NULL, 0);
        verify->sha1_client = crypto_hash_init(CRYPTO_HASH_ALG_SHA1, NULL, 0);
        verify->sha1_server = crypto_hash_init(CRYPTO_HASH_ALG_SHA1, NULL, 0);
        verify->sha1_cert = crypto_hash_init(CRYPTO_HASH_ALG_SHA1, NULL, 0);
        if (verify->md5_client == NULL || verify->md5_server == NULL ||
            verify->md5_cert == NULL || verify->sha1_client == NULL ||
            verify->sha1_server == NULL || verify->sha1_cert == NULL) {
                tls_verify_hash_free(verify);
                return -1;
        }
        return 0;
}


void tls_verify_hash_add(struct tls_verify_hash *verify, const u8 *buf,
                         size_t len)
{
        if (verify->md5_client && verify->sha1_client) {
                crypto_hash_update(verify->md5_client, buf, len);
                crypto_hash_update(verify->sha1_client, buf, len);
        }
        if (verify->md5_server && verify->sha1_server) {
                crypto_hash_update(verify->md5_server, buf, len);
                crypto_hash_update(verify->sha1_server, buf, len);
        }
        if (verify->md5_cert && verify->sha1_cert) {
                crypto_hash_update(verify->md5_cert, buf, len);
                crypto_hash_update(verify->sha1_cert, buf, len);
        }
}


void tls_verify_hash_free(struct tls_verify_hash *verify)
{
        crypto_hash_finish(verify->md5_client, NULL, NULL);
        crypto_hash_finish(verify->md5_server, NULL, NULL);
        crypto_hash_finish(verify->md5_cert, NULL, NULL);
        crypto_hash_finish(verify->sha1_client, NULL, NULL);
        crypto_hash_finish(verify->sha1_server, NULL, NULL);
        crypto_hash_finish(verify->sha1_cert, NULL, NULL);
        verify->md5_client = NULL;
        verify->md5_server = NULL;
        verify->md5_cert = NULL;
        verify->sha1_client = NULL;
        verify->sha1_server = NULL;
        verify->sha1_cert = NULL;
}
